Remove restriction that the min. trade amount must be >= 50% of the amount

[HenrikJannsen]

We restrict the min. trade amount to 50% of the amount.
I think we should avoid to add further restrictions beside the needed (and complicated) ones for the trade limits.

[github-actions]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[HenrikJannsen]

Still relevant

[github-actions]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.